Process of flash-proofing fabrics



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Patented Not. 7, 1922.

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WARREN 1K. LEWIS, 01E NEWTON, AND HAROLD C. WEBER, OF MILTON, MASSAGE-TUfilE'llTS, ASSIGNOBS T LEWIS, GREEN, MOADAM & KNOWLAND, 0F BOSTUN,IMASSA- CIBIUSETTS, A COPAR'JDNERSHIP CONSISTING- 0F WARREN K. ,nnwrs,WILLIAM GREEN, WILLIAM MGADAESI, AND RICHARD Gt. KNQWLANID.

PRUCESS UL FLASH-JPRQOFING- FABRICS.

151 0 Drawing.

ducing the infiammabilityof fabricsmade of vegetable materials such ascotton, jute or flax and is particularly concerned with cotton' fabricswhich have a nap surface, such as flannelette. One objection to the useof fabrics of this character is the fact that a spark or fiamestrikingthe surface of the goods, even for a very brief instant, is liable toset fire to the nap, and the fire so started flashes quickly over thesurface of the cloth. Thus there is. great dangerthat fire catch- "ingin garments made of material of this character will result inburning-the wearer very seriously, even though. the fire originated in amanner which would be entirely harmless if the arment were made or adifierent' materia lln'order to overcome this difgiculty attempts havebeen made heretofore o treat fabpics of this character in a mannerdesigned to render them permanently less inflammable.

, character are frequently termed in the trade flash-proofing processesand they will be 1 so designated hereinafter.

- The present inventlon aims to devise a process of flash-proofingfabrics which can be economically practised on a commercial scale andwhich will give superlor results. According to the present process theflan- I nelette or other fabric to. be flash-proofed is first immersedin an aqueous solution of a salt of a metal (other than the alkalmeearths) whose hosphate is insoluble. Pref erably we use a uminiumsulphate. -Any desired strength of solution can 'beused, say, forinstance, about 1 perment.v After the fabric has'become thoroughlywetwith the solution it is removed from this bat and the surplus solutionis squeezed out .o it by running it throu h a suitable wringer ormangle. The clot is next'iersed in 'an Processes of this thusprecipitated on the Application an @ctober 1a. rem. Serial no. 331.1055.

aqueous solution of some soluble phosphate, preferably a sodiumphosphate. This solutlon may be of any suitable strength, say, 1 to 2per cent. The cloth is then wrung out of the second solution, is washed,and dried.

We believe that this process is essentially a process of dyeing withcolorless dye. That is, amordant in the commonly accepted sense of theterm is a compound with an affinity for textile fibres on the one handand for certain specific dye stufis on the other.

The fibre is treated first with a mordant,

combination ensuing. The combination of fibre and mordant is thentreated with a dye stufi', the dye stufi' whichotherwise would notcombine with the'fibre, now combining with the mordant fixed to thefibre, produc v ing a'permanent combination. in the same way aluminium,sulphate, while not ordinarily considered a mordant for cotton becauseits aflinit aflinity f r the animal fibres, wool and silk, does,nevertheless, combine with cotton; when so combined it will then combinewith phosphate ion, thereby fixing the phosphate radical to the cottonin exactly the way a -mordant fixes a dye to the fibre and securingthereby a result not otherwise obtainable. In other words, the reactionsthat take place in this process are of the same nature as those thatcharacterize any dyeing process using a mordant.

Thatthe result is not-due solely to the precipitation of an insoluble;compound for cotton is so muchless than-its within the voids of thefibre itself, is proven by the fact that barium phosphate and similarinsoluble compounds fibre are not permanently affix'ed; they are readilydusted out, whereas the aluminium phosphate is held with great tenacity.

In the process above described the aluminium phosphate is the materialthat actually does the flash-proofing, but this material is incorporatedwith the cloth in such away tvgat it remains permanently in the goods.

e have found it impossible to obtain this result simply by mechanicallypadding or loading the fabric phate. It is evident, therefore, that something more than "a mechanical union be tween the aluminium phosphate andthe fabrio is produced-by this process.

sulphate, calcium tlll Illlll with aluminium phos- While we havehereinbefore named the materials that we prefer to use in practisingthis process, it is obvious that other materials than those specificallymentioned can be used. Inasmuch as it ordinarily is undesirable to havethe flash-proofing process affect the color of the goods, the salt inthe first bath should be one that will form acts as a mordant, and theactive elements in both solutions being capable of reacting with eachother to form in the goods an insoluble salt of one of the phosphoricacids.

What is claimed as new 'is:

1. The process of flash-proofing fabrics which consists in immersing thefabric successively in two solutions, one of aluminium sulphate and theother of sodium phosphate.

2. The process of flash-proofing fabrics which consists in immersing thecloth in a solution of aluminium sulphate, squeezing the surplussolution out of the cloth, next immersing the cloth in a solution ofsodium phosphate, and finally washing and drying the 'cloth.

3. The process of flash-proofing fabrics which consists in treating thefabric successively with two solutions, one of said solutions containinga soluble aluminum salt, and the other containing a soluble phosphate.

In testimony whereof we have signed our names to this specification.

WARREN K. LEWIS. HAROLD CL WEBER.

